Search and replace with mapping from a mapper file in a target file Post: 302735363

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Top Forums Shell Programming and Scripting Search and replace with mapping from a mapper file in a target file Post 302735363 by bakunin on Saturday 24th of November 2012 01:45:41 PM

11-24-2012

Registered User

As far as i can see "sed" should be up to the task: go through your mapper file, one line at a time. There are 4 bytes in every line:

1. a "src" character
2. a ">"
3,4. a "target" character.

It is easy to divide in 2 shell variables:

Code:

cat mapper | while read line ; do
     src="${line%???}"
     tgt="${line#??}"
done

Now use these variables to replace all original characters to translated ones. You have to mark you original characters somehow to make sure you don't translate characters twice during various passes. In this case we escape all characters initially with a backslash and remove these as we translate. This way we can - by searching for backslashes in the resultfile - find out if our mapper file is completely covering the input. If still backslashes are there some characters didn't get translated.

Code:

sed 's/./\\&//g' /path/to/infile > workfile # mask all characters with "\"

cat mapper | while read line ; do
     src="${line%???}"
     tgt="${line#??}"
     sed 's/\\'"${src}"'/'"${tgt}"'/g' workfile > workfile.tmp
     mv workfile.tmp workfile
done
mv workfile /path/to/outfile

This silently presupposes the backslash "\" not to be used in your inputfile. Replace it with another (unused) character if this is not the case.

I hope this helps.

bakunin

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multipath

MULTIPATH(8)						   Linux Administrator's Manual 					      MULTIPATH(8)

NAME

       multipath - Device mapper target autoconfig

SYNOPSIS

       multipath [-v verbosity] [-d] [-h|-l|-ll|-f|-t|-F] [-p failover|multibus|group_by_serial|group_by_prio|group_by_node_name] [device]

DESCRIPTION

       multipath is used to detect multiple paths to devices for fail-over or performance reasons and coalesces them

OPTIONS

       -v  level
	      verbosity, print all paths and multipaths

		   0	       no output

		   1	       print the created or updated multipath names only, for use to feed other tools like kpartx

		   2 +	       print all info : detected paths, coalesced paths (ie multipaths) and device maps

       -h     print usage text

       -d     dry run, do not create or update devmaps

       -l     show the current multipath topology from information fetched in sysfs and the device mapper

       -ll    show the current multipath topology from all available information (sysfs, the device mapper, path checkers ...)

       -f     flush a multipath device map specified as parameter, if unused

       -F     flush all unused multipath device maps

       -t     print internal hardware table to stdout

       -p policy
	      force maps to specified policy:

		   failover    1 path per priority group

		   multibus    all paths in 1 priority group

		   group_by_serial
			       1 priority group per serial

		   group_by_prio
			       1  priority group per priority value. Priorities are determined by callout programs specified as a global, per-con-
			       troller or per-multipath option in the configuration file

		   group_by_node_name
			       1 priority group per target node name. Target node names are fetched in /sys/class/fc_transport/target*/node_name.

       device update only the devmap the path pointed by device is in.	device is in the /dev/sdb (as shown by udev in the $DEVNAME  variable)	or
	      major:minor format.  device may alternatively be a multipath mapname

SEE ALSO

       multipathd(8), multipath.conf(5), kpartx(8), udev(8), dmsetup(8) hotplug(8)

AUTHORS

       multipath was developed by Christophe Varoqui, <christophe.varoqui@free.fr> and others.

								     July 2006							      MULTIPATH(8)